... because I can't find them, and I'm using them a lot now.
Once you get the hang of using Orientation for controlling cameras (well - for controlling a null that your camera's parented to), you can do beautiful craning/orbiting motions. They end up feeling nicer than using Euler rotations as AE calcs them with quaternions, so my camera follows "Great circle" paths rather than interpolating the axes separately. Sometimes the effect is subtle, but sometimes it's a huge improvement - particularly if your camera moves near one of the poles.
But Orientation is difficult to manage from the parameters - it's much easier to hit 'W' and use the crosshair manipulator on screen. If I have a typical camera -> cameraRotNull setup, for orbiting around an object, I'll always want to control my camera's height by orienting the null round its local X axis, but the camera's rotation around the object needs to be done using the World's Y axis.
Hence much switching between local and world.
(I'm on a Mac, AE CC 2015)